Adhesion and reliability of bonds between metal structures, such as a wire bond between a bond pad and a wire or a bond interface between metal interconnects in an integrated circuit, are primary concerns within articles that include electronic devices. Various factors may impact the adhesion and reliability of the bonds, such as but not limited to the presence of surface contaminants, surface topology of the metal structures, and chemistry of the metal structures to be bonded.
Efforts to maximize adhesion between the metal structures have focused on chemical surface treatment to minimize or eliminate surface contaminants that could lead to corrosion (thereby reducing reliability) or that negatively influence adhesion. However, chemical surface treatment alone is insufficient to maximize adhesion and reliability of the bonds. Further, some chemical surface treatments have an undesirable result of introducing chemically stable surface species on contact surfaces of the metal structures that are to be bonded, and the chemically stable surface species may impeded kinetics of bond formation between the metal structures or may otherwise impact desired formation of the bond. For example, wet or dry chemical processing of contact surfaces is often conducted, e.g., using various acids or halogenated compounds (depending upon the particular materials of the contact surfaces) to remove metal oxides from the contact surfaces. Particularly when fluorine-containing etchants are employed, such chemical processing may give rise to fluorine-doped metal oxides, which are chemically stable and deter corrosion, but which also mask surface morphology of the contact surface and may slow adhesion kinetics.
Adhesion and reliability of bonds between metal structures, such as a wire bond between a bond pad and a wire or a bond interface between metal interconnects in an integrated circuit, are primary concerns within articles that include electronic devices. Various factors may impact the adhesion and reliability of the bonds, such as but not limited to the presence of surface contaminants, surface topology of the metal structures, and chemistry of the metal structures to be bonded.
Alloying or doping of the metal structures, i.e., modification of the chemistry of the metal structures to be bonded, has also been employed to promote intermetallic formation during bonding between the metal structures. However, alloying or doping may require expensive target retrofitting and extensive reliability requalification for the bonded metal structures.
Accordingly, it is desirable to provide methods of effecting bond adhesion between metal structures with maximized bond adhesion and reliability between the metal structures, and articles that include metal structures bonded with maximized bond adhesion and reliability, in addition to or as an alternative to the approaches that involve chemical surface treatment and/or alloying or doping of the metal structures. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.